The title isochroman ( 8 ) was synthesized as a suitable substrate for
acetoxylation studies leading to an intermediate of type (4), expected to afford,
on condensation with diketen, the fungal metabolite "rotiorin" type linear
product (1). Cyclocondensation of alcohol (6), obtained by the reduction of
ketone (5) with paraform in the presence of anhydrous aluminum chloride
afforded the dimethoxyisochroman (7). Demethylation of (7) using boron
tribromide in dichloromethane furnished the title isochroman (8).